This invention relates to injection molding and more particularly to an injection molding system in which a heated nozzle having a tip is actuated between a retracted open position and a closed forward position in which the tip is seated in a gate to provide valve gating.
Heated nozzles are well known in the injection molding art, by they are normally seated in a fixed position in a well in the cavity plate. Valve gating is normally provided by a reciprocating valve pin which extends through a central bore in the nozzle. An example of this type of system is shown in the applicants' Canadian patent application Ser. No. 524,969 entitled "Mechanism for Valve Gated Injection Molding with Resilient Retaining Ring" which was filed Dec. 10, 1986. More recently, the applicants' Canadian patent application Ser. No. 542,182 entitled "Injection Molding Multiple Nozzle Valve Gating System" which was filed July 15, 1987 discloses a multi-cavity system in which a number of nozzles are fixed to a common manifold and the manifold and nozzles are actuated together.
Similarly, a system in which a number of injection molding probes are valve gated simultaneously by actuating a common manifold is shown in the applicants' U.S. Pat. No. 4,669,971 entitled "Valve Gate Probe" which issued June 2, 1987. Fixed nozzles having a pointed tip and a sealing and locating flange are well known, as shown, for instance, in the applicants' Canadian patent application Ser. No. 549,519 entitled "Injection Molding Nozzle with Resilient Sealing and Locating Flange" which was filed Oct. 16, 1987. However, none of the prior art shows a system for valve gating a single gate by actuating the nozzle without using the pressurized melt to open the valve.